Improvement in piston-packing



GEGRGE GWYNN.

Improvement in Piston Packing.

' No.l23,891. Patented Feb. 20,1872.

UNITED STATES PATENT FrIcE.

GEORGE GWYNN, OF-NEW YORK, N. Y.

IMPROVEMENT IN PISTON-PACKING.

Specification forming part of Letters Patent No. 123,891, dated February 20, 1872.

Specification describing certain Improve ments in Packing, invented by GEORGE GWYNN, :of the city, county, and State of New York.

This invention consists in a novel preparation of the fabric of which the packing is composed in part or in whole, whereby it is not only made close and durable, but when applied to a rod or working-part, avoids heating, and is self-lubricating.

The accompanying drawing represents a roll packing of spiral form, applicable to stuflingboxes and other purposes, the same being constructed in accordance with the invention.

A isthe prepared fabric, which may either be used for gasket or roll-packin g. This fabric, which may be made of linen toweling or cotton sheet, I treat to give it the properties hereinbet'ore mentioned, with a composition made up of paraftine, India rubber, lead, zinc, graphite or plnmbago, wood, sawdust, and quicksilver. Thus, I take of parafline, two pounds; India rubber, four ounces; lead, one and onehalf pounds; zinc, eight ounces; graphite or plumbago, eight ounces; tine hard-wood sawdust, (box-wood or lignum vitae,) eight ounces; and quicksilver, one ounce.

To prepare this composition, the zinc is first melted in a close retort, and the quicksilveradded by introducing it through a suitable cock or valve, taking care to keep the temperature low enough to prevent evaporation o the quicksilver. WVhen cold this mixture is re duced to powder, and the plumbago having been pulverized, and the lead filed up into powder, all these are mixed with the saw-dust. The parafline and rubber are melted together and mixed, and are spread with a spatula over the fabric while the latter is laid upon a table heated by steam or otherwise. The powdered ingredients are then rubbed with a roller or or other suitable implement into the coating of parattine and India rubber, and the fabric is ready for use. The proportions of the several ingredients of the composition may be to some extent varied without materially affecting its etliciency, but I believe that the best results maybe obtained from the proportions speciiied. B is a core, made of hemp, cotton, or other fibrous material, having its fibers either straight or twisted upon which the strip of prepared fabric A is wound spirally.

\Nhat I claim as my invention, and desire to secure by Letters Patent, is

The woven fabric A, cut and prepared with the composition substantially as herein specified, in combination with the core B, for the purpose set forth.

GEORGE GWYNN. \Vitnesses:

FRED. HAYNES, R. E. RABEAU. 

